For press systems that are utilized for metal forming, a ram is typically driven towards and away from a press bed such that, in use, a tool that is mounted between the ram and the press bed deforms a work piece. Generally, the tool, or die, comprises two parts known as die sets. In use, these die sets are generally attached one part to the ram and the other part to the press bed. Typically, these die sets includes guides for holding/clamping and/or aligning the work piece.
The ram of the press may be reciprocated by means of crankshaft acting through a connecting rod where the crankshaft is driven by a motor through a clutch and/or a flywheel. Alternately, hydraulics may be utilized as well. In any arrangement, the press ram is advanced towards the press bed and work piece is deformed by the die sets mounted therebetween.
It will be appreciated that different dies are required for different pressing operations. In this regard, a plurality of dies may be mounted between the ram and press bed of a single press. Further, a single work piece may progress from die to die in the press in order to be formed into a completed part. In this regard, different dies on the press may perform different forming/stamping functions. For instance, some dies may be operative to bend or otherwise fold a work piece while other dies may cut or punch the work piece.
In many instances, it may become necessary to forcibly remove the work piece from a die after pressing. That is, it may become necessary to strip the work piece from the die such that additional work may be done to the work piece and/or the work piece may be removed from the press. In this regard, it has been common practice to utilize individual dies that are equipped with an individual pressure module (e.g., stripping module or power pack) that is built into the die. The pressure module compresses when the ram is advanced to the press bed. Upon the ram being retracted from the press bed, the pressure module is operative to expand and, thereby, apply a force (i.e., stripping force) that may remove a work piece from the die. Such pressure modules may be in the form of compression springs, rubber stripper tubes or self-contained nitrogen cylinders (e.g., found in a punch holder).
Incorporation of the pressure module/stripper into individual dies has several drawbacks. For instance, incorporation of an individual stripper into or onto each individual die increases the cost of each die set. Further, if it becomes desirable to increase or decrease the pressure exerted by the pressure module/stripper (e.g., to accommodate different metals and/or metal thickness, etc.), the entire die must be removed from the press and disassembled in order to access the pressure module. At such time, components of the pressure module may be removed from the die in order to replace those components with different sized components. In instances where one or more nitrogen cylinders are utilized, adjustability of the pressure exerted by the cylinders may be simplified. However, such a nitrogen pressure modules are typically too expensive to utilize with every die/tool constructed.
It is against this background and with the desire to improve the adjustability of pressure modules/strippers within a metal pressing system that the present modular power pack assembly has been developed.